About four years ago I was given an opportunity to learn more about horse health and grazing when I discovered I was the owner of a wonderful reining horse who had developed laminitis from stress issues with his feet. Hence the beginning of my journey to learn more about the laminitis disease process as well as diet and grazing. I was shocked to learn how much pasture management plays into the management of this disease.

If your horse is overweight or has suffered a metabolic disorder (such as laminitis, Cushing's disease, equine metabolic syndrome, insulin resistance, polysaccharide storage myopathy, etc.) one of the best resources for reducing sugars and simple carbohydrates is Katy Watts, Rocky Mountain Research and Consulting, Inc. Katy has DVDs and other educational materials available for purchase for a reasonable price.

In horses, “fat” is not healthy and the related high sugar and non-structural carbohydrate issues in hay and grass may explain why we are now seeing so many overweight individuals with metabolic disorders and insulin resistance problems. The way we've been grazing horses (overgrazed pastures) and the types of pastures we've developed (grass species with extremely high levels of sugars and carbohydrates, good for early-age market animals) may be contributing to serious horse health issues. Even for healthy horses, watching your horse’s waistline and doing your best to keep him/her in good health is an important first step to avoiding further health issues.

Here are some dos and don’ts that can help to reduce the sugar and simple carbohydrate load in your horse’s diet.

Bob wearing his grazing muzzle

Bob in his grazing muzzle only gets out on pasture for a few minutes in the early morning.


  • Learn what a healthy weight for your horse is. Talk with your vet or consult a weight chart such as the one discussed in this article.
  • Get a scale and weigh your horse’s daily hay. Not only will this eliminate overfeeding, but it will save you money by not wasting hay (from overfeeding.) Don't cheat when feeding; a one-pound difference in a feeding is a big difference!
  • Night grazing can be very useful. The best time to graze while gaining maximum benefit of forage without adding extra fat on your horse is between 3 am until 10 am. At this time pasture plants have used up most of the accumulated sugar built up during the day. Since there’s not many of us that want to set our alarm clocks to 2:45 am, what works for some horse owners is to turn horses out as late as possible in the evening (say, 10 pm), and bringing them in the next morning before heading off to work. Another useful alternative to night grazing is turning horses out on pasture in the early morning (like 6 am) and bringing them in by about 10am when plant production of sugar becomes high once again. 
  • Graze horses during the active growing seasons (spring and early summer.) Don’t be fooled by the late summer grass as brown grasses can be very high in sugars! Pastures are healthiest for horses (i.e. lowest in sugars) during the active growing season when plants are green and not stressed (i.e., not brown).
  • Implement a rotational grazing program to help avoid overgrazing. The greatest amount of sugar in a grass plant is in the bottom three inches, so rotate pastures before they are grazed below three inches.Shady pastures and cloudy days will result in lower carb and sugar levels in grasses. Rotating horses to shady pastures may be an option for high-risk individuals.
  • Easy keepers on pasture may need a grazing muzzle, a device that fastens on a horse’s head and only allows the horse to eat through a 2-inch hole at the bottom of the muzzle. An internet search will give you several options, plus tips on safety and how to use them.
  • Exercising a horse as little as 30 minutes per day, three times per week, can make a big health change by improving his overall metabolism. Most horses with metabolic issues are not getting enough exercise. Horses (like their humans!) need regular exercise as part of their standard care regime.
  • Treat each horse as an individual. Just like with people, the dietary needs for one horse may not be the same for another horse.
Bob wearing his grazing muzzle

Weighing your horse’s daily hay will eliminate accidental overfeeding and save you money.


  • Don't allow grain or treats in your horse’s diet. Except for specifically developed low-carbohydrate products, all grain, complete feeds and concentrates add huge amounts of sugars and non-structural carbohydrates to a horse’s diet. Horses only require these in their diets when lacking in energy or weight.
  • Don’t overgraze pastures. The greatest amount of sugar in a grass plant is concentrated in the bottom three inches. Allowing horses to overgraze pastures adds high amounts of sugars to their diets.
  • Don’t graze during cool weather (under 40 degrees) and especially if it has frosted. Pasture plants store carbohydrates at very high levels during these times, making it a particularly dangerous time to graze. This is a key issue and will play havoc with an at-risk horse’s metabolic condition.
  • Don’t graze pastures that are under stress or drought conditions (yellow, brown or dried-out grass) as these are likely to be high in sugars. Essentially, anything that stresses the plant increases the concentration of sugars in it, because stressors (i.e., drought, poor fertilization, cold weather) reduce the plant's ability to use those sugars to grow new plant tissue.
  • During long periods of sunny weather, eliminate or substantially reduce grazing time for at-risk individuals. Consider grazing late at night instead (see above.)
  • Confining a horse in a stall along with reducing physical demands sets the stage for serious metabolic problems.

Remember: Seek help from a veterinarian and/or and other professionals experienced in this area especially if you have an at-risk individual. Also, keep in mind that for any changes you institute, you need to give the situation time in order to evaluate its effectiveness. Any changes in diet need to be done gradually, over a period of time, in order to give the horse’s gut time to adjust. For more on this topic see The Grass is Not Always Greener